Remixed Left Case by pigaro

Last crawled date: 3 years, 1 month ago

This is yet another remix of the excellent Teaching Tech Ender 3 all-in-one electronics left case. The changes for this case include a different DC-DC converter and relay module from the ones used in the original design. The DC-DC converter is a DZS Elec model number Super LM2596S, 9 – 36 V input, 5.2 V output up to 6 A (depending on input voltage). The DC-DC converter has both a USB-A connector and a wire output. I used a USB-A to USB-C right angle (both ends) cable to provide power to the Raspberry Pi 4B. I used the wire connectors to power a 5 V Nocturna NF-A4x20 fan. The choice of parts allowed me to put this together without soldering, although connecting to the relay might have been easier if the wires had been tinned.
The DC-DC converter fits into a well and is not attached to the case. The reason for this is that it allows the converter to be removed (without disconnecting any wires) to provide access to the micro SD slot of the Raspberry Pi. Access is not easy, but I have been able to remove and install the micro SD card. Be careful – I broke one card.
I used a USB-A to USB-C cable that had right angle ends (UGREEN). I would recommend a right angle end on at least the Raspberry Pi side (micro USB for Raspberry Pi versions 3 or less, USB-C for version 4). There might be enough space for a regular connector on the USB-A side, depending on the bend radius of the cable. The shortest cable was 1.5 feet, which is way too long and needed to be coiled.
The relay module is a HiLetgo 5 V, one-channel relay, model 3-01--340, with a different footprint than the original design. I only included one relay to control 24 V power to the printer side. I don't think a second relay would fit. Note that I had to leave off one of the four screws due to interference with the USB cable.
Getting all the wires in was a tight fit, and the wire I used for the relay was probably too fine (high gauge) and difficult for the relay connector to clamp. I wired the DC-DC converter directly to one set of unused connectors in the power supply, so the Raspberry Pi is powered whenever the power switch is on.
One other change to the original design was to provide through holes for the Raspberry Pi and relay screw mounts. The M3x8 mm screws bottomed out before contacting the circuit boards. Adding a hole though the case allowed the screws to tighten to the board and they only protrude slightly through the case. I had the opposite problem on the right side case. The screws protruded too far, so I made some cylinders to offset the screws.